A. A nonconforming building or structure, other than a single- family dwelling, shall not be added to or enlarged in any manner unless such nonconforming building or structure and use, including all additions and enlargements, are made to conform to all regulations of the district in which it is located.
B. A single-family dwelling, nonconforming as to bulk, may be added to or enlarged without seeking a variation, if all ground floor additions or enlargements conform to all setback, height and lot coverage limitations of the district in which the property is located. A second story addition or dormer to such buildings is allowed, provided such additions or enlargements do not exceed the footprint of the existing nonconforming dwelling, and such addition or enlargement does not otherwise present a significant nuisance or hazard. (1965 Code title 6 § 501.4)